From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932296AbWGLA0X (ORCPT ); Tue, 11 Jul 2006 20:26:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932293AbWGLA0X (ORCPT ); Tue, 11 Jul 2006 20:26:23 -0400 Received: from pat.uio.no ([129.240.10.4]:53214 "EHLO pat.uio.no") by vger.kernel.org with ESMTP id S932296AbWGLA0W (ORCPT ); Tue, 11 Jul 2006 20:26:22 -0400 Subject: Re: [PATCH] struct file leakage From: Trond Myklebust To: Andrew Morton Cc: dev@sw.ru, linux-kernel@vger.kernel.org, kuznet@ms2.inr.ac.ru, devel@openvz.org In-Reply-To: <20060711163254.5ac8941b.akpm@osdl.org> References: <44B2185F.1060402@sw.ru> <20060710030526.fdb1ca27.akpm@osdl.org> <1152619446.5745.16.camel@lade.trondhjem.org> <20060711163254.5ac8941b.akpm@osdl.org> Content-Type: text/plain Date: Tue, 11 Jul 2006 20:26:02 -0400 Message-Id: <1152663962.5681.58.camel@lade.trondhjem.org> Mime-Version: 1.0 X-Mailer: Evolution 2.6.1 Content-Transfer-Encoding: 7bit X-UiO-Spam-info: not spam, SpamAssassin (score=-3.184, required 12, autolearn=disabled, AWL 1.63, FORGED_RCVD_HELO 0.05, RCVD_IN_SORBS_DUL 0.14, UIO_MAIL_IS_INTERNAL -5.00) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2006-07-11 at 16:32 -0700, Andrew Morton wrote: > Trond Myklebust wrote: > > > > > > - if (error) > > > > + if (error) { > > > > + /* Does someone understand code flow here? Or it is only > > > > + * me so stupid? Anathema to whoever designed this non-sense > > > > + * with "intent.open". > > > > + */ > > > > + if (!IS_ERR(nd->intent.open.file)) > > > > + release_open_intent(nd); > > > > return error; > > > > + } > > > > nd->flags &= ~LOOKUP_PARENT; > > > > if (nd->last_type == LAST_BIND) > > > > goto ok; > > > > > > > > > > It's good to have some more Alexeycomments in the tree. > > > > > > I wonder if we're also needing a path_release() here. And if not, whether > > > it is still safe to run release_open_intent() against this nameidata? > > > > > > Hopefully Trond can recall what's going on in there... > > > > The patch looks correct, except that I believe we can skip the IS_ERR() > > test there: if we're following links then we presumably have not tried > > to open any files yet, so the call to release_open_intent(nd) can be > > made unconditional. > > Sorry, but phrases like "looks correct" and "I believe" don't inspire > confidence. (Although what you say looks correct ;)) Are you sure? We do need the call to release_open_intent(), since otherwise we will leak a struct file. The question is whether we can optimise away the IS_ERR() test. In my opinion, we can. > And do we also need a path_release(nd) in there? No. do_follow_link() should release the path for us on error. Replacing with a 'goto exit' would therefore be a mistake. Cheers, Trond